/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.juli;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.logging.Formatter;
import java.util.logging.LogRecord;

/**
 * Provides same information as default log format but on a single line to make
 * it easier to grep the logs. The only exception is stacktraces which are
 * always preceded by whitespace to make it simple to skip them.
 */
/*
 * Date processing based on AccessLogValve.
 */
public class OneLineFormatter extends Formatter {

	private static final String LINE_SEP = System.getProperty("line.separator");
	private static final String ST_SEP = LINE_SEP + " ";

	/* Timestamp format */
	private static final String timeFormat = "dd-MMM-yyyy HH:mm:ss";

	/**
	 * The size of our global date format cache
	 */
	private static final int globalCacheSize = 30;

	/**
	 * The size of our thread local date format cache
	 */
	private static final int localCacheSize = 5;

	/**
	 * Global date format cache.
	 */
	private static final DateFormatCache globalDateCache =
			new DateFormatCache(globalCacheSize, timeFormat, null);

	/**
	 * Thread local date format cache.
	 */
	private static final ThreadLocal<DateFormatCache> localDateCache =
			new ThreadLocal<DateFormatCache>() {
				@Override
				protected DateFormatCache initialValue() {
					return new DateFormatCache(localCacheSize, timeFormat, globalDateCache);
				}
			};

	@Override
	public String format(LogRecord record) {
		StringBuilder sb = new StringBuilder();

		// Timestamp
		addTimestamp(sb, record.getMillis());

		// Severity
		sb.append(' ');
		sb.append(record.getLevel().getLocalizedName());

		// Thread
		sb.append(' ');
		sb.append('[');
		sb.append(Thread.currentThread().getName());
		sb.append(']');

		// Source
		sb.append(' ');
		sb.append(record.getSourceClassName());
		sb.append('.');
		sb.append(record.getSourceMethodName());

		// Message
		sb.append(' ');
		sb.append(formatMessage(record));

		// Stack trace
		if (record.getThrown() != null) {
			sb.append(ST_SEP);
			StringWriter sw = new StringWriter();
			PrintWriter pw = new PrintWriter(sw);
			record.getThrown().printStackTrace(pw);
			pw.close();
			sb.append(sw.getBuffer());
		}

		// New line for next record
		sb.append(LINE_SEP);

		return sb.toString();
	}

	protected void addTimestamp(StringBuilder buf, long timestamp) {
		buf.append(localDateCache.get().getFormat(timestamp));
		long frac = timestamp % 1000;
		buf.append('.');
		if (frac < 100) {
			if (frac < 10) {
				buf.append('0');
				buf.append('0');
			} else {
				buf.append('0');
			}
		}
		buf.append(frac);
	}
}
